A self-contained generator/fumigator and delivery system is described herein that provides for sealed containment to store, isolate and protect two or more solid and/or liquid reactants in separate chambers. Upon activation, the container facilitates robust mixing of the reactants, the containment thereof and allows the release of a pre-determined amount of gaseous products, e.g., chlorine dioxide, carbon dioxide and others, into a targeted volume of water, air or other solution.